Sunday, March 28, 2010

I don't usually do posts solely as link dumps, but I will today. Last week, former All-Star Nomar Garciaparra was on ESPN's Baseball Tonight show about modern baseball statistics. He proceeded to make the cliched statement that "there's no stat yet that measures heart." A few days later, baseball writer Joe Posnanski posted an extremely thoughtful (and thought-provoking) response on his website. Poz's article is respectful and non-sardonic (which, you have to admit, is sometimes hard to find in the blogging community) while being effective in getting his point across. It is definitely one of the best baseball articles I have read.

Thursday, March 25, 2010

Earlier today, Joe Girardi made the official announcement that we've all been waiting for --- Phil Hughes has been selected as the team's 5th starter in 2010. It's hardly a surprise, given Hughes' solid spring performance (and also since it had been unofficially reportedmultiple times). This leaves the fates of Alfredo Aceves, Joba Chamberlain, and Sergio Mitre undetermined (the other man up for the job, Chad Gaudin, was released earlier today). Girardi said that the three would compete for jobs in the bullpen, and was clear that nobody had a guaranteed spot. When asked if Chamberlain would slot back into the 8th inning role, Girardi answered, "You've gotta earn your spots." As Ben Kabak at River Ave. Blues speculated this afternoon, maybe Girardi was referring to Chamberlain's spot on the team and not as just as primary setup man. Conceivably, the Yankees could send him to Triple A Scranton and keep him stretched out as a starting pitcher, though I figure that won't happen.

Congratulations to Hughes. It is easy to forget that Hughes was in the rotation for much of his injury-derailed 20-year-old season in 2007, and started the third game of the year in 2008 before injuries bit him once again. I must say that Chamberlain was my pick for the job since his innings were managed so that he could pitch 200 innings this year, while Hughes will still have some restrictions. However, Hughes would need to pitch one way or another, so it's not an easily reconcilable problem --- though it is the kind of problem that many teams would love to have.

Sunday, March 14, 2010

For this week's reliever profile, I will turn to the Mexican Gangster, Alfredo Aceves. Signed by the Yankees out of the Mexican League in 2008, Aceves shot through the entire system that year, making his major league debut on August 31st. After making two relief appearances, he replaced the struggling Darrell Rasner as the Yankees' 5th starter in the rotation, where he stayed for the rest of the year. In his six games overall, he compiled a pretty 2.40 ERA despite less impressive peripherals that caused his FIP to stand at 4.80.

The Ace started 2009 at Triple A Scranton, but was called up to the majors before a May 4th game against the Red Sox. He made an admirable long-relief appearance in that game, picking up for starter Phil Hughes. Aceves had many of those types of outings in 2009; in fact, in 29 of his 42 relief appearances, he pitched at least an inning and a third. Since he has been a starter throughout his career, manager Joe Girardi felt comfortable putting him in situations in which he needed length from his relievers. To illustrate Aceves' versatility, I would like to display a double-axis frequency chart: the primary axis on the left shows the number of innings Aceves pitched in each relief outing, and the secondary axis shows the inning that Aceves entered the game. (click on any of the graphs for a larger image)

The graph shows that Aceves most frequently entered the ballgame in the 6th inning, though throughout the season, he entered a game in every inning except the 3rd. Two inning appearances were the most common for Aceves, though he had his fair share of outings both longer and shorter. The other thing about Aceves' appearances is that they were often in relatively high leverage spots. As I discussed a few months ago, the general trend for relievers is that more innings pitched per game, the lower the average Leverage Index will be. Aceves' 2009 season was one of the rare circumstances in which a reliever maintained both a high AIPGR and LI. This next chart shows the LI frequency for each of Aceves' relief appearances (LI of 1 is the "average" situation).

Aceves may be best known for his versatility and command, but his pitches themselves are nothing to scoff at. I turn to PITCHf/x to look at his "stuff."

Average Speed

Max Speed

pfx_x

pfx_z

spin_angle

FF

91.18

93.8

-5.59

9.83

209.56

FC

88.48

90.9

0.07

5.80

177.70

CU

78.95

82.9

4.84

-7.03

38.23

CH

82.43

87.9

-8.76

6.88

231.59

Nice low-90s fastball, hard cutter, curveball with lots of break, and a changeup with a ~10 mph fastball differential. The fastball is pretty straight - it's presumably a four-seamer, though there may be a few two-seamers mixed in as well. Here are some pitch results to help us judge the effectiveness of the pitches.

Pitch#

Pitch%

Swing Rate

Whiff Rate

Wide Zone Rate

Zone Whiff Rate

Chase Rate

Watch Rate

FF

511

41.2%

.485

.173

.562

.156

.250

.352

FC

277

22.4%

.556

.149

.603

.108

.221

.281

CU

231

18.6%

.316

.260

.580

.148

.260

.597

CH

220

17.8%

.632

.353

.477

.293

.410

.219

1239

99.2%

.496

.218

.559

.167

.280

.362

SLGCON

RSv/100

xRSv/100

FF

.525

0.72

0.44

FC

.467

0.76

-0.59

CU

.406

1.02

0.76

CH

.317

3.69

2.54

.457

1.31

0.64

Looks like some nice stuff there. He can find the strike zone with all four pitches while maintaining a solid whiff rate. One thing I found surprising was the abundance of groundballs from his curveball and (relative) lack of groundballs from his cut fastball.

Aceves has seemed to earn a reputation as a pitcher without patterns, never being predictable with his pitch tendencies. One way I wanted to test this was by splitting up his pitch mix versus righties and versus lefties to see if there was anything particularly unusual. The biggest difference (and understandably so) is in the changeup, which tails into righty hitters. There are significantly more changeups to lefties, so that it can be utilized as moving away from the hitter.

The final chart I would like to display takes into account overall pitch selection based on count. The easiest way to show this in graphical form is to use run expectancy. The ideal pitching situation in terms of run expectancy is an 0-2 count, for which there is a run expectancy of ~ -.1 runs scored below average. Thus, an 0-2 count is displayed as the furthest point on the graph to the left. Conversely, the count with the highest run expectancy is a 3-0 count, which is worth .22 runs above average. The 3-0 count is furthest to the right on the graph. The first pitch of any at-bat always has a run expectancy of 0.

Basically, this graph shows the pitch percentage in each of the 12 counts. I wanted to show some sort of relativity to pitch selection in other counts, so to create this graph I divided the pitch percentage of the given count by the overall pitch percentage. Here is how Aceves used his four pitches, according to the weighted pitch mix (my apologies for the cluttered-ness of the graph).

The general trend, at least for his 2009 outings, appears to be that Aceves prefers the changeup and curveball ahead in the count, and the fastball and cutter for when he's behind.

Aceves began this Spring Training allowing no baserunners in his first 6 spring training innings. He has impressed in 10 innings so far, and even though spring training stats count for virtually nothing, his strong performance has led to whispers about a potential starting role come April. He has impeccable control (his 1.7 BB/9 rate out of the bullpen last year was 4th best in baseball), confidence in all four of his pitches, and enough stuff to fool batters when he needs to. The Yankees have quite an enviable situation, because Aceves would be a welcomed addition to any major league rotation.

Saturday, March 6, 2010

In this post, I would like to profile David Robertson. Personally, I find him to be the most intriguing of the Yankees' bullpen pitchers due to his unconventional method of obtaining a superb strikeout rate.

Drafted (17th round) as a 21 year old in 2006, Robertson shot up through the Yankees' minor league system, dominating at every level:

League

IP

ERA

FIP

K/9

BB/9

A

47

0.77

1.31

12.83

2.87

A+

33 1/3

1.08

2.33

9.99

4.05

AA

22 2/3

1.19

1.17

13.90

3.18

AAA

49 2/3

1.99

1.79

13.77

4.17

MiL

152 2/3

1.30

1.67

12.67

3.60

Robertson made his major league debut against the Mets in June of 2008, and he stayed with the big club for two months before being optioned back to Triple A (he would make another cameo as a September call-up). He had an ugly 5.34 ERA over his 30 1/3 innings of work (25 appearances), but his 36 strikeouts (10.38 K/9) impressed; he also posted a much better 3.53/3.72 FIP/xFIP. Though Robertson was left off of the Opening Day roster in 2009, by the end of May, he was in the Yankee bullpen for good. For the 2009 regular season, Robertson put up a solid 3.30 ERA in 43 2/3 innings (45 appearances). His FIP/xFIP were both excellent at 3.05/3.20. What was most remarkable about Robertson in 2009 was his strikeout rate. His 12.98 K/9 for the year was second in all of major league baseball to Jonathan Broxton. Interestingly, nearly 15% of all at-bats against Robertson resulted in a called strike three, which was far and away the highest mark in the majors (the league average for called strikeout% is about 4.5%). This is helped by his 24.4% called strike rate (called strikes/total pitches), which was also best in the major leagues (~16% league average for relievers). Robertson relied on deception in the minor leagues, as well; in his Triple A stint from 2008-2009 (844 pitches overall), he had a similar called strike rate of 23.7%. But what is so special about Robertson that causes opposing batters to watch so many pitches? Can some PITCHf/x data help us out here?

Pitch

Average Speed

Max. Speed

pfx_x

pfx_z

FF

91.75

95.5

-0.01

11.14

CU

79.34

83.3

3.98

-8.69

CH

85.52

87.9

-8.08

9.85

SL

83.46

85.8

6.87

2.95

(click graphs for larger image)

Pitch

Pitch#

Pitch%

Swing%

Whiff%

Wide Zone%

Chase%

Watch%

FF

654

75.9%

35.8%

26%

59%

21.4%

52.3%

CU

172

20%

50.6%

27.6%

42.4%

40.2%

28.8%

CH

25

2.9%

24%

33.3%

32%

16.7%

37.5%

SL

11

1.3%

36.4%

0%

27.3%

75%

66.7%

862

99.5%

38.4%

26.3%

54.5%

26.9%

48.5%

Pitch

SLGCON

RSv/100

FF

.543

0.88

CU

.773

-0.26

.596

0.48

A lot of both called and swinging strikes from Robertson's fastball, it looks like. The pitch is pretty much straight, sometimes cutting slightly. He also utilizes a hard curveball with a significant amount of vertical drop. I also found a few tailing changeups in the data, and some other pitches that looked like sliders. But for the most part, Robertson is all about the fastball and curveball. And particularly, the fastball. The strikeout breakdown below shows the third strike for each of Robertson's 63 strikeouts in 2009.

Pitch

Total

Called

Swinging

Total%

Called%

Swinging%

FF

38

20

18

60.3%

31.7%

28.6%

CU

24

7

17

38.1%

11.1%

27%

SL

1

1

0

1.6%

1.6%

0%

63

28

35

100%

44.4%

55.6%

The pitch that earned Robertson the most strikeouts in 2009 was a "watched" fastball. It's pretty ridiculous that he could consistently get batters to watch the straight fastball - moreover, one that averaged under 92 mph for the season. There is clearly something pretty special going on here. From the outside, Robertson's motion itself doesn't seem too deceptive, but there are all sorts of ways that a pitcher can hide the ball and make it appear that it's being thrown harder. There has been some work at Baseball Prospectus regarding perceived velocity, and I'm sure that there will be plenty more research done on the phenomenon. I can't say that I would have much to offer on the topic, so I will leave that as something of a mystery for now.

Another thing worth noting about Robertson's 2009 season was his dramatic velocity increase. In April and May, he was often working in the upper 80s and sat around 90 mph, but in August, he was averaging over 93 mph. The increase is illustrated clearly by Robertson's velocity graph over the course of the season (all pitches):

If you look closely, you can see a dip right near the end of the season. That marks Robertson's return from a three-week long hiatus due to a shoulder injury. On River Ave. Blues, there's an interesting post that suggested that increased velocity itself might have had something to do with Robertson's injury. Mid season, Robertson tweaked his delivery at Dave Eiland's heed (in order to add velocity), and it's not unreasonable to believe that this adjustment wound up hurting Robertson. Since Robertson's velocity remained strong into the beginning of September, I'm having a hard time believing that Robertson's injury was that serious. I don't claim to know a whole lot about injuries, but would I believe that the drop following his return had more to do with a lack of rehab time (the Yankees needed him for the playoff bullpen) than actual harm to the shoulder. (EDIT: According to the YES Network gun, Robertson sat around 93 mph and hit 95 mph in his first Spring Training appearance on Friday. The radar gun has seemed pretty accurate so far, so that is definitely an encouraging sign.)

So, what can we look for in Robertson's 2010 campaign? Sustaining a ~13 K/9 is obviously unrealistic, but it's clear that there's something special about his stuff. His xFIP has been higher than his FIP during both years, and since he's a flyball pitcher (41.3% FB rate for both years), home runs are something to watch out for. Manager Joe Girardi seemed to gain confidence in Robertson as the season wore on - Robertson picked up his first "hold" of the year against Seattle on August 15th, and picked up four more right before his shoulder injury. I fully expect Phil Hughes or Joba Chamberlain (personally, I think that it will be Hughes) to be the full time "set up guy" this season, but Robertson has shown that he should be in the mix for some important innings.